Our aim is to train young scientists to design and conduct research on significant problems in cancer by combining information and approaches from different scientific disciplines, including basic cellular and molecular biology, epidemiology clinical trials and studies, and behavioral-social sciences. The rationale behind this program is to produce researchers who can excel in the increasingly complex and specialized environments required for future cancer research. The IDTG is a highly competitive and demanding training program. Trainees work closely with two mentors who provide distinct, complementary areas of expertise (for example, by studying basic molecular and cellular mechanisms of neoplasia in combination with epidemiological analyses of related risk factors; or by participating in clinical research studies while studying behavioral or environmental factors that influence therapeutic outcomes). Our trainee projects transcend the traditional boundaries separating the molecular and cellular, clinical, epidemiologic and social cancer sciences. As a result, the IDTG and Program differ fundamentally in focus, goals and training plans from other pre- and post-Doctoral training programs in the Seattle biomedical research community. The Interdisciplinary Training Grant in Cancer Research supports two separate types of interdisciplinary trainees. The first are dual-mentor PhD candidates and postdoctoral fellows, who work within two separate research groups to study a common problem in cancer using unique, and yet complementary research disciplines. The second are graduate students who are enrolled in a dual-degree program that allows Ph.D. students in the Molecular and Cellular Biology (MCB) graduate program to earn a concurrent Masters of Science degree in Epidemiology. Trainees in either type of track are supported by this training grant as part of a broad initiative in Seattle to create a scientific culture where interdisciplinary cancer research and training is encouraged and fostered. Three separate institutions (The Fred Hutchinson Cancer Research Center, the University of Washington, and the Institute for Systems Biology) have served as research sites for IDTG trainees and their mentors. The IDTG faculty mentors each have primary appointments at one of those three institutions, and the majority have additional cross-institutional affiliate appointments within the UW graduate school and/or in the Seattle Cancer Consortium. We have created an environment across all these institutions where graduate students and postdoctoral fellows can become conversant in the goals, assumptions, logic, methods, and vocabulary of multiple research disciplines.